CVE-2024-56674
📋 TL;DR
A race condition in the Linux kernel's virtio_net driver can cause a kernel crash when network interfaces are repeatedly brought down and up under heavy transmit load. This affects systems using virtio networking, particularly virtual machines and containers. The vulnerability results in a denial of service but does not allow privilege escalation or data compromise.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to complete system crash and downtime, requiring physical or remote console access to reboot.
Likely Case
System crash requiring reboot when network interfaces are frequently toggled under heavy load, causing service disruption.
If Mitigated
Minimal impact if interfaces aren't frequently toggled or systems aren't under heavy network load.
🎯 Exploit Status
Reproduction script provided in CVE description requires local access and ability to toggle network interfaces. Could be weaponized for DoS attacks in multi-tenant environments.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 3ddccbefebdbe0c4c72a248676e4d39ac66a8e26 and b4294d4ac61fbb382811a1d64eaf81f446ce2af4
Vendor Advisory: https://git.kernel.org/stable/c/3ddccbefebdbe0c4c72a248676e4d39ac66a8e26
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.
🔧 Temporary Workarounds
Avoid frequent interface toggling
linuxPrevent scripts or operations from rapidly bringing network interfaces up and down under heavy load.
Limit network interface permissions
linuxRestrict which users can toggle network interfaces using sudoers or capabilities.
# Remove network management from users
# In /etc/sudoers, remove 'ip' command access
# Or use capabilities: setcap -r /sbin/ip
🧯 If You Can't Patch
- Monitor for frequent interface state changes and investigate unusual patterns
- Implement strict change control for network interface operations
🔍 How to Verify
Check if Vulnerable:
Check if system crashes when running: while :; do ip l set eth0 down; ip l set eth0 up; done under heavy network TX loadCheck Version:
uname -rVerify Fix Applied:
After patching, attempt reproduction script and verify no kernel panic occurs📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs mentioning 'dql_completed' or 'virtio_net'
- System crash/reboot logs after network interface changes
- Frequent 'ip link set' commands in audit logs
Network Indicators:
- Sudden loss of network connectivity followed by system reboot
SIEM Query:
event.action:"ip link set" AND (event.outcome:"failure" OR event.outcome:"success") | stats count by host.name, user.name | where count > threshold